Short cycle times for cost-efficient processing in lyophilized formulations

Pharmaceutical scientists who bulk freeze dry need to foremost identify what quality factors are of a priority during cycle development since the economics of freeze-drying do not allow for both the cost-efficient production and the ability to obtain the highest quality score across all quality factors. Consider; morphology, activity, dissolution, long-term storage, packaging and cost.

Surrogate-based analysis and optimization for the design of heat sinks with jet impingement

Heat sinks are widely used for cooling electronic devices and systems. Their thermal performance is usually determined by the material, shape, and size of the heat sink. With the assistance of computational fluid dynamics (CFD) and surrogate-based optimization, heat sinks can be designed and optimized to achieve a high level of performance. In this paper, the design and optimization of a plate-fin-type heat sink cooled by impingement jet is presented. The flow and thermal fields are simulated using the CFD simulation; the thermal resistance of the heat sink is then estimated. A Kriging surrogate model is developed to approximate the objective function (thermal resistance) as a function of design variables. Surrogate-based optimization is implemented by adaptively adding infill points based on an integrated strategy of the minimum value, the maximum mean square error approach, and the expected improvement approaches. The results show the influence of design variables on the thermal resistance and give the optimal heat sink with lowest thermal resistance for given jet impingement conditions.

In situ diagnostics and prognostics of wire bonding faults in IGBT modules for electric vehicle drives

This paper presents a diagnostic and prognostic condition monitoring method for insulated-gate bipolar transistor (IGBT) power modules for use primarily in electric vehicle applications. The wire-bond-related failure, one of the most commonly observed packaging failures, is investigated by analytical and experimental methods using the on-state voltage drop as a failure indicator. A sophisticated test bench is developed to generate and apply the required current/power pulses to the device under test. The proposed method is capable of detecting small changes in the failure indicators of the IGBTs and freewheeling diodes and its effectiveness is validated experimentally. The novelty of the work lies in the accurate online testing capacity for diagnostics and prognostics of the power module with a focus on the wire bonding faults, by injecting external currents into the power unit during the idle time. Test results show that the IGBT may sustain a loss of half the bond wires before the impending fault becomes catastrophic. The measurement circuitry can be embedded in the IGBT drive circuits and the measurements can be performed in situ when the electric vehicle stops in stop-and-go, red light traffic conditions, or during routine servicing.

Pyrolysis and combustion of municipal solid wastes:evaluation of synergistic effects using TGA-MS

A thermogravimetric methodology was developed to investigate and semi-quantify the extent of synergistic effects during pyrolysis and combustion of municipal solid waste (MSW). Results from TGA-MS were used to compare the pyrolysis and combustion characteristics of single municipal solid waste components (polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), branches (BR), leaves (LV), grass (GR), packaging paper (PK), hygienic paper (HP) and cardboard (CB)) and a mixture (MX) of PP, BR and CB. Samples were heated under dynamic conditions at 20°C/min from 25°C to 1000°C with the continuous record of their main evolved fragments. Synergistic effects were evaluated by comparing experimental and calculated weight losses and relative areas of MS peaks. Pyrolysis of the mixture happened in two stages, with the release of H2, CH4, H2O, CO and CO2 between 200 and 415°C and the release of CH4, CxHy, CO and CO2 between 415 and 525°C. Negative synergistic effect in the 1st stage was attributed to the presence of PP where the release of hydrocarbons and CO2 from BR and CB was inhibited, whereas positive synergistic effects were observed during the 2nd degradation stage. In a second part of the study, synergistic effects were related to the dependency of the effective activation energy (Eα) versus the conversion (α). Higher Eαs were obtained for MX during its 1st stage of pyrolysis and lower Eαs for the 2nd stage when compared to the individual components. On the other hand, mostly positive synergistic effects were observed during the combustion of the same mixture, for which lower Eαs were recorded.

Vacuum brazing of alumina ceramic to titanium for biomedical implants using pure gold as the filler metal

One of the many promising applications of metal/ceramic joining is in biomedical implantable devices. This work is focused on vacuum brazing of C.P titanium to 96% alumina ceramic using pure gold as the filler metal. A novel method of brazing is developed where resistance heating of C.P titanium is done inside a thermal evaporator using a Ta heating electrode. The design of electrode is optimized using Ansys resistive heating simulations. The materials chosen in this study are biocompatible and have prior history in implantable devices approved by FDA. This research is part of Boston Retinal implant project to make a biocompatible implantable device (www.bostonretina.org). ^ Pure gold braze has been used in the construction of single terminal feedthrough in low density hermetic packages utilizing a single platinum pin brazed to an alumina or sapphire ceramic donut (brazed to a titanium case or ferrule for many years in implantable pacemakers. Pure gold (99.99%) brazing of 96% alumina ceramic with CP titanium has been performed and evaluated in this dissertation. Brazing has been done by using electrical resistance heating. The 96% alumina ceramic disk was manufactured by high temperature cofired ceramic (HTCC) processing while the Ti ferrule and gold performs were purchased from outside. Hermetic joints having leak rate of the order of 1.6 × 10-8 atm-cc/ sec on a helium leak detector were measured. ^ Alumina ceramics made by HTCC processing were centreless grounded utilizing 800 grit diamond wheel to provide a smooth surface for sputtering of a thin film of Nb. Since pure alumina demonstrates no adhesion or wetting to gold, an adhesion layer must be used on the alumina surface. Niobium (Nb), Tantalum (Ta) and Tungsten (W) were chosen for evaluation since all are refractory (less dissolution into molten gold), all form stable oxides (necessary for adhesion to alumina) and all are readily thin film deposited as metals. Wetting studies are also performed to determine the wetting angle of pure gold to Ti, Ta, Nb and W substrates. Nano tribological scratch testing of thin film of Nb (which demonstrated the best wetting properties towards gold) on polished 96% alumina ceramic is performed to determine the adhesion strength of thin film to the substrate. The wetting studies also determined the thickness of the intermetallic compounds layers formed between Ti and gold, reaction microstructure and the dissolution of the metal into the molten gold.^

Practical dynamic thermal management on Intel desktop computer

Fueled by increasing human appetite for high computing performance, semiconductor technology has now marched into the deep sub-micron era. As transistor size keeps shrinking, more and more transistors are integrated into a single chip. This has increased tremendously the power consumption and heat generation of IC chips. The rapidly growing heat dissipation greatly increases the packaging/cooling costs, and adversely affects the performance and reliability of a computing system. In addition, it also reduces the processor's life span and may even crash the entire computing system. Therefore, dynamic thermal management (DTM) is becoming a critical problem in modern computer system design. Extensive theoretical research has been conducted to study the DTM problem. However, most of them are based on theoretically idealized assumptions or simplified models. While these models and assumptions help to greatly simplify a complex problem and make it theoretically manageable, practical computer systems and applications must deal with many practical factors and details beyond these models or assumptions. The goal of our research was to develop a test platform that can be used to validate theoretical results on DTM under well-controlled conditions, to identify the limitations of existing theoretical results, and also to develop new and practical DTM techniques. This dissertation details the background and our research efforts in this endeavor. Specifically, in our research, we first developed a customized test platform based on an Intel desktop. We then tested a number of related theoretical works and examined their limitations under the practical hardware environment. With these limitations in mind, we developed a new reactive thermal management algorithm for single-core computing systems to optimize the throughput under a peak temperature constraint. We further extended our research to a multicore platform and developed an effective proactive DTM technique for throughput maximization on multicore processor based on task migration and dynamic voltage frequency scaling technique. The significance of our research lies in the fact that our research complements the current extensive theoretical research in dealing with increasingly critical thermal problems and enabling the continuous evolution of high performance computing systems.

Leakage temperature dependency aware real-time scheduling for power and thermal optimization

Catering to society's demand for high performance computing, billions of transistors are now integrated on IC chips to deliver unprecedented performances. With increasing transistor density, the power consumption/density is growing exponentially. The increasing power consumption directly translates to the high chip temperature, which not only raises the packaging/cooling costs, but also degrades the performance/reliability and life span of the computing systems. Moreover, high chip temperature also greatly increases the leakage power consumption, which is becoming more and more significant with the continuous scaling of the transistor size. As the semiconductor industry continues to evolve, power and thermal challenges have become the most critical challenges in the design of new generations of computing systems. ^ In this dissertation, we addressed the power/thermal issues from the system-level perspective. Specifically, we sought to employ real-time scheduling methods to optimize the power/thermal efficiency of the real-time computing systems, with leakage/ temperature dependency taken into consideration. In our research, we first explored the fundamental principles on how to employ dynamic voltage scaling (DVS) techniques to reduce the peak operating temperature when running a real-time application on a single core platform. We further proposed a novel real-time scheduling method, “M-Oscillations” to reduce the peak temperature when scheduling a hard real-time periodic task set. We also developed three checking methods to guarantee the feasibility of a periodic real-time schedule under peak temperature constraint. We further extended our research from single core platform to multi-core platform. We investigated the energy estimation problem on the multi-core platforms and developed a light weight and accurate method to calculate the energy consumption for a given voltage schedule on a multi-core platform. Finally, we concluded the dissertation with elaborated discussions of future extensions of our research. ^

Uniquely Identifiable Tamper-Evident Device Using Coupling between Subwavelength Gratings

Reliability and sensitive information protection are critical aspects of integrated circuits. A novel technique using near-field evanescent wave coupling from two subwavelength gratings (SWGs), with the input laser source delivered through an optical fiber is presented for tamper evidence of electronic components. The first grating of the pair of coupled subwavelength gratings (CSWGs) was milled directly on the output facet of the silica fiber using focused ion beam (FIB) etching. The second grating was patterned using e-beam lithography and etched into a glass substrate using reactive ion etching (RIE). The slightest intrusion attempt would separate the CSWGs and eliminate near-field coupling between the gratings. Tampering, therefore, would become evident. Computer simulations guided the design for optimal operation of the security solution. The physical dimensions of the SWGs, i.e. period and thickness, were optimized, for a 650 nm illuminating wavelength. The optimal dimensions resulted in a 560 nm grating period for the first grating etched in the silica optical fiber and 420 nm for the second grating etched in borosilicate glass. The incident light beam had a half-width at half-maximum (HWHM) of at least 7 µm to allow discernible higher transmission orders, and a HWHM of 28 µm for minimum noise. The minimum number of individual grating lines present on the optical fiber facet was identified as 15 lines. Grating rotation due to the cylindrical geometry of the fiber resulted in a rotation of the far-field pattern, corresponding to the rotation angle of moiré fringes. With the goal of later adding authentication to tamper evidence, the concept of CSWGs signature was also modeled by introducing random and planned variations in the glass grating. The fiber was placed on a stage supported by a nanomanipulator, which permitted three-dimensional displacement while maintaining the fiber tip normal to the surface of the glass substrate. A 650 nm diode laser was fixed to a translation mount that transmitted the light source through the optical fiber, and the output intensity was measured using a silicon photodiode. The evanescent wave coupling output results for the CSWGs were measured and compared to the simulation results.

Implementation of X-ray diffraction in the measurement of residual thermal strains

Microelectronic systems are multi-material, multi-layer structures, fabricated and exposed to environmental stresses over a wide range of temperatures. Thermal and residual stresses created by thermal mismatches in films and interconnections are a major cause of failure in microelectronic devices. Due to new device materials, increasing die size and the introduction of new materials for enhanced thermal management, differences in thermal expansions of various packaging materials have become exceedingly important and can no longer be neglected. X-ray diffraction is an analytical method using a monochromatic characteristic X-ray beam to characterize the crystal structure of various materials, by measuring the distances between planes in atomic crystalline lattice structures. As a material is strained, this interplanar spacing is correspondingly altered, and this microscopic strain is used to determine the macroscopic strain. This thesis investigates and describes the theory and implementation of X-ray diffraction in the measurement of residual thermal strains. The design of a computer controlled stress attachment stage fully compatible with an Anton Paar heat stage will be detailed. The stress determined by the diffraction method will be compared with bimetallic strip theory and finite element models.

An augmented reality pipeline to create scenes with coherent illumination using textured cuboids

Shadows and illumination play an important role when generating a realistic scene in computer graphics. Most of the Augmented Reality (AR) systems track markers placed in a real scene and retrieve their position and orientation to serve as a frame of reference for added computer generated content, thereby producing an augmented scene. Realistic depiction of augmented content with coherent visual cues is a desired goal in many AR applications. However, rendering an augmented scene with realistic illumination is a complex task. Many existent approaches rely on a non automated pre-processing phase to retrieve illumination parameters from the scene. Other techniques rely on specific markers that contain light probes to perform environment lighting estimation. This study aims at designing a method to create AR applications with coherent illumination and shadows, using a textured cuboid marker, that does not require a training phase to provide lighting information. Such marker may be easily found in common environments: most of product packaging satisfies such characteristics. Thus, we propose a way to estimate a directional light configuration using multiple texture tracking to render AR scenes in a realistic fashion. We also propose a novel feature descriptor that is used to perform multiple texture tracking. Our descriptor is an extension of the binary descriptor, named discrete descriptor, and outperforms current state-of-the-art methods in speed, while maintaining their accuracy.

Desenvolvimento de um painel sanduíche com carga de particulado oriundo de resíduo lignocelulósico para aplicação em produtos na área de equipamentos de proteção

This work aims to study and investigate the use of a hybrid composite polymer formed with blanket aramid (Kevlar 29) fiber blanket flax fiber and particulate dry endocarp of coconut (Cocos nucifera Linn), using as matrix an epoxy resin based thermoset for use in areas of protective equipment. Besides such material is used an aluminum plate, joined to the composite by means of glue based on epoxy and araldite commercial. The manufacturing process adopted was manual lamination (Hand Lay Up) to manufacture the hybrid composite. After the composite is prepared, an aluminum plate is subjected to pressure and glued to cure the adhesive. Layers of veil will also be used to separate the particulate from the linen blanket layer without disturbing the alignment of the fibers of the blankets. To characterize the mechanical and physical behavior was manufactured a plate of 800 x 600 mm of the hybrid composite, which were removed specimens for tests of water absorption to saturation; density; impact test (Charpy) and two test specimens for ballistic testing 220 mm x 200 mm to make a comparative study between the dry state and saturated water absorption and thus see the ballistic performance of these two conditions. The test was applied to make a comparative study of fracture in these two conditions, caused by penetrating ballistic missile (38 and 380). To test the impact (Charpy) will analyze the absorbed energy, fracture appearance and lateral contraction, also in dry condition and saturation of absorbed water, thereby analyzing situations where the impact load is relevant, such as bumps and shocks produced by stone, metal or wooden bars among others. The proposed configuration, along with the tests, has the purpose, application in the fields of equipment against ballistic impact, such as helmets; bullet proof vests; shields; protective packaging and other items to be identified in this research.

Obtenção e caracterização de um compósito polimérico de matriz poliéster e reforço/carga de tecido plano de algodão

He was obtained and studied the feasibility of using TPA (Tissue Cotton Plan) screen type, for bagging, with a weight of 207.9 g / m2 in a composite of orthophthalic crystal polyester resin matrix. The process for obtaining the composite was tested against the maximum number of layers that could be used without compromising the processability and manufacturing of CPs in compression mold. Five configurations / formulations were selected and tested at 1, 4, 8, 10 and 12 layers of cotton tissue - TPA. TPA was not subjected to chemical treatment, only by passing a mechanical washing process. The composite in its various configurations / formulations was characterized to determine its physical properties. The properties of the composite were higher viability resistance to bending, approaching the matrix and impact resistance, superiority in relation to the polyester resin. Another property that has shown good result compared to other composite has water absorption. Analyzing all the properties set the settings / formulations with higher viability were TA8 and TA10, by combining good processability and higher mechanical strength, with lower loss compared to polyester resin matrix. The composite showed lower mechanical behavior of the resin matrix for all the formulations studied except the impact resistance. The SEM showed a good adhesion between the layers of TPA and polyester resin matrix, without the presence of micro voids in the matrix confirming the efficient manufacturing process of the samples for characterization. The composite proposed proved to be viable for the fabrication of structures with low requests from mechanical stresses, and as demonstrated for the manufacture of solar and wind prototypes, and packaging, shelving, decorative items, crafts and shelves, with good visual appearance.

Obtenção e caracterização de um compósito polimérico de matriz poliéster e reforço/carga de tecido plano de algodão

He was obtained and studied the feasibility of using TPA (Tissue Cotton Plan) screen type, for bagging, with a weight of 207.9 g / m2 in a composite of orthophthalic crystal polyester resin matrix. The process for obtaining the composite was tested against the maximum number of layers that could be used without compromising the processability and manufacturing of CPs in compression mold. Five configurations / formulations were selected and tested at 1, 4, 8, 10 and 12 layers of cotton tissue - TPA. TPA was not subjected to chemical treatment, only by passing a mechanical washing process. The composite in its various configurations / formulations was characterized to determine its physical properties. The properties of the composite were higher viability resistance to bending, approaching the matrix and impact resistance, superiority in relation to the polyester resin. Another property that has shown good result compared to other composite has water absorption. Analyzing all the properties set the settings / formulations with higher viability were TA8 and TA10, by combining good processability and higher mechanical strength, with lower loss compared to polyester resin matrix. The composite showed lower mechanical behavior of the resin matrix for all the formulations studied except the impact resistance. The SEM showed a good adhesion between the layers of TPA and polyester resin matrix, without the presence of micro voids in the matrix confirming the efficient manufacturing process of the samples for characterization. The composite proposed proved to be viable for the fabrication of structures with low requests from mechanical stresses, and as demonstrated for the manufacture of solar and wind prototypes, and packaging, shelving, decorative items, crafts and shelves, with good visual appearance.

Castles in the air: the life, times and influence of the Reverend Moses Harvey (1820-1901).

The period from 1874 to 1901 was a time of significant transition in the economic and political life of Newfoundland. Twenty years into responsible government and with Confederation on the backburner, the colony’s politicians turned their attention to economic diversification, landward development and carving out the island’s place in the British Empire. The period saw both economic prosperity and retrenchment; the construction of a trans-insular railway; the adoption of policies to foster agriculture, forestry, manufacturing and mining; and diplomatic efforts to resolve France’s outstanding claims on the northwest coast of the island. At the same time, the government made an attempt to intervene directly in its primary industry, the fisheries. It created a Fisheries Commission in 1889 that recommended conservation measures and artificial propagation as ways to restore the health of some of the island’s fish stocks. They also proposed new methods of curing, packaging and marketing Newfoundland’s cod, as well as a complete overhaul of the truck system. A major player in both the public and private debates surrounding all of these subjects was the Reverend Moses Harvey. Along with being minister of the Free Church of Scotland in St. John’s, Harvey was one of Newfoundland’s most active promoters in the late nineteenth century. He served as the media mouthpiece for both Prime Minister William Whiteway and Prime Minister Robert Thorburn; editing the Evening Mercury – the official organ of the Liberal Party and then the Reform Party – from 1882 to 1883 and 1885 until 1890. As well, Harvey wrote regular columns on Newfoundland issues for newspapers in London, New York, Boston, Montreal, Toronto, and Halifax. He also produced numerous books, articles, encyclopedia entries, and travel guides outlining the island’s attractions and its vast economic potential. In short, Harvey made a significant contribution in shaping the way residents and the outside world viewed Newfoundland during this period. This thesis examines late nineteenth-century Newfoundland through the writing of Moses Harvey. The biographical approach offers a fuller, more nuanced account of some of the major historical themes of the period including the politics of progress, opening up the interior, railway construction and attitudes toward the fisheries. It also provides an insider’s prospective on what led to some of the major political decisions, policy positions or compromises taken by the Whiteway and Thorburn governments. Finally, a more detailed review of Harvey’s work exposes the practical and political differences that he had with people like D.W. Prowse and Bishop Michael Howley. While these so-called “boomers” in Newfoundland’s historiography agreed on broad themes, they parted ways over what should be done with the fisheries and how best to channel the colony’s growing sense of nationalism.

Split Up. Smart feature per contenitori asettici per liquidi basata sulla progettazione strutturale e grafica di finestre trasparenti

Il lavoro di tesi concerne la progettazione di un contenitore asettico per liquidi. In particolare, consiste nella creazione di aree/finestre trasparenti, ricavate sulla superficie del contenitore, con la funzione di indicatore di livello del liquido. Gli step che hanno delineato il lavoro consistono in un'analisi brevettuale, studio dei materiali di produzione, verifica tecnica e strutturale, progettazione grafica e test di validazione dell'idea.